Normally, the functionality of semiconductor chips is not processed individually, but rather simultaneously for a plurality of semiconductor chips, in the composite on a semiconductor wafer. It is possible to dispose several thousand components on such a wafer, depending on the chip size and the wafer size, which components must then be separated at the end of the production process.
German Patent No. DE 103 50 036 describes a method that is intended to simplify the separation of the chips. This method may also be used in particular in the production of thinned chips whose functionality is implemented only in a surface layer of the semiconductor substrate. In this instance, the lateral chip boundaries are defined with the aid of etched trenches that completely penetrate the surface layer of the substrate. Furthermore, surface micromechanical methods are used to produce cavities under the surface layer, so that in the region of a cavity the individual chip regions are connected to the substrate layer below this cavity via supporting elements only. To separate the chips, these supporting elements are then cut mechanically, for example in a pick-off process as part of the individual chip mounting.
The surfaces of the chips manufactured according to the known method are unprotected. They must subsequently be passivated individually, that is, sequentially. This proves problematic in practice, in particular for extremely thin chips.